Anodic dissolution process and apparatus therefor



4 Sheets-Sheet 2 NELSON G. KLING s. BARABAS ET AL (IIIIIIIIIA ANODIC DISSOLUTION PROCESS AND APPARATUS THEREFOR Filed 001;. 14, 1966 Mgrch 31, 1970 March 31, 1970 Filed Oct. 14, 1966 S. BARABAS ET AL ANODIC DISSOLUTION PROCESS AND APPARATUS THEREFOR 4 Shets-Sheet 5 ONE CVCLE I H I I EA ECTRDZWE ORA/Al VAL V45 W456 V4.4 V6

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4 TI'ORNEY ANODIG DISSOLUTION PROCESS AND APPARATUS THEREFOR Filed Oct. 14, 1966 March 31, 1970 s. BARABAS ET AL 4 Sheets-Sheet 4 INVENTORS 5/Lv/o BRRABRS JACK ISREELI By MILTON H. PELAVIN NELSON G. KLING CLL RTTORNEY United States Patent 3,503,862 ANODIC DISSOLUTION PROCESS AND APPARATUS THEREFOR Silvio Barabas, Pierrefonds, Quebec, Canada, and Jack Isreeli, Mamaroneck, and Milton H. Pelavin, White Plains, N .Y., and Nelson G. Kling, Passaic, N.J., assignors to Technicon Corporation, a corporation of New York Filed Oct. 14, 1966, Ser. No. 586,818 Int. Cl. 301k 3/00; C23b /72 US. Cl. 204-225 6 Claims ABSTRACT OF THE DISCLOSURE This invention relates to automatic analysis and, more particularly, to the automatic dissolution of a sample metal into a carrier liquid for the analysis of said metal.

In the chemical quantitative analysis of a metal for a constituent thereof, it is customary to dissolve the metal into a carrier liquid so that it may subsequently be treated with reagents and the result of the reaction may be detected visually or instrumentally. The conventional process required a manual weighing out of the sample metal on an analytical balance, and its dissolution in a predetermined volume of acid or alakali. This was laborious and time consuming, particularly when many samples had to be rapidly prepared and analyzed for examples as a means of effective production quality control. In the US. Patent application of Silvio Barabas et al., Ser. No. 566,153, filed July 18, 1966, there is disclosed a system for the electrolytic dissolution of a metallic solid in an electrolyte using the metallic solid as an anode against a suitable cathode, and applying a predetermined amount of current for a predetermined period of time; after which the electrolyte is removed for analysis.

It is an object of this invention to provide a system for the automatic, rapid, electrolytic dissolution of a metallic solid in an electrolyte, which applies a blending action to the dissolved sample to ensure the provision of a uniform, reproducible sample for analysis.

' Another object of this invention is the provision of a system which automatically dissolves each of a plurality of metallic solids in an electrolyte, and which sequentially transmits each of the sample-containing electrolytes for processing, such as quantitative analysis for at least one constituent thereof.

A feature of this invention is the provision of a system including a first chamber to receive electrolyte, an anode formed from the sample metal and a cathode; means to automatically dispose the electrolyte, the anode, and the cathode in said first chamber and to subsequently remove them therefrom; means to automatically supply an electrical current to the electrodes; and means to receive the sample containing electrolyte from said first chamber and to transmit a predetermined quantity thereof as a flowing stream to an analysis apparatus.

Another feature of this invention is the provision of a system including a transport mechanism supporting a plurality of metallic solids and for sequentially disposing each of the metallic solids in a respective supply of Patented Mar. 31, 1970 electrolyte, means to automatically supply an electrical current to the electrodes; and means to transmit a predetermined respective quantity of each of the sample containing electrolytes as a flowing stream of liquid.

These and other objects, features and advantages of this invention will become apparent from the following specifications thereof taken in conjunction with the accompanying drawing in which:

FIG. 1 is a front view in elevation of a first embodiment of this invention;

FIG. 2 is a side view in elevation, in a cross-section taken along plane 2-2 of FIG. 1;

FIG. 3 is a rear view in elevation, in a cross-section taken along plane 3-3 of FIG. 2;

FIG. 4 is a detail view in plan, in a cross-section taken along plane 44 of FIG. 1;

FIG. 5 is a timing chart indicating the sequence of operation of various of the components of the system of FIG. 1; and

FIG. 6 is a perspective view of a second embodiment of this invention.

The apparatus, as shown in FIG. l, comprises a base 10, and a column 12. Disposed within the base are a start push switch 14, a pilot light 16, a timing relay 18 for controlling the duration of the current pulse to the electrodes, a timing relay 20 for controlling the duration of the supplying of sample containing electrolyte to the automatic analysis apparatus; a DC. ammeter 22 for indicating the current applied to the electrodes; a push switch 24 for connecting the ammeter into the supply circuit; a D.C. voltmeter 26 for indicating the voltage applied to the electrodes; a toggle switch 28 for connecting the voltmeter into the supply circuit; and a circuit breaker 30.

Supported by the column are an electrolytic receptacle assembly 32, a blending receptacle assembly 34, an electrode support assembly 36, an anode 38 and a cathode 40. Disposed within the column is a programmer assembly 42.

The column 12 includes a front wall 44, a rear wall 46, a left side wall 48, and a right side wall 50, all secured to the top of the base by a system of angle brackets 52. The programmer assembly 42 includes an electric motor 54 having a solenoid operated clutch 55 in a housing which is fixed to the right side wall 50 by a plurality of stand-off brackets 56. A gear 58 is fixed to the output shaft of the motor, and is meshed with a gear 60 fixed to a shaft 62 which is journaled between the side walls 48 and 50. A cam 64 is also fixed to the gear 60 about the shaft 62, and a cam 66 is also fixed to this shaft. Eight timing cams 68, 70, 72, 74, 75, 76, 78 and 80 are adjustably screwed to the shaft by respective set screws. Eight snap action switches 82, 84, 86, 88, 89, 90, 92 and 94 are fixed on two threaded rods 96, 98 between the side walls to be respectively actuated by the timing cams.

The electrode support assembly 36 includes an upper shaft 100 and a lower shaft 102 which are respectively journaled through and beyond the side walls 48, 50. An upper pair of arms 104, 106 are respectively coupled at their rear ends to the projecting ends of the shaft 100 and a lower pair of arms 108, 110 are respectively coupled at their rear ends to the projecting ends of the shaft 102. A cross-bar 112 has a pair of depending arms 114, 116 fixed to its ends. The cross-bar and the upper end of the arm 114 are pivotally mounted at 118 to the front end of the arm 104. The cross-bar and the upper end of the arm 116 are pivotally mounted at 120 to the front end of the arm 106. The lower end of the arm 114 is pivotally mounted at 122 to the front end of the arm 108; and the lower end of the arm 116 is pivotally mounted at 124 to the front end of the arm 110. A crank arm 126 has its rear end adjustably fixed to the shaft 100 by a set screw, and its front end pivotally mounted at 128 to the upper end of a pitman 130. The lower end of the pitman carries a cam follower roller '132 which rides on the cam 64. A slot 134 in the pitman receives a guide bolt 136 which is fixed to the side wall 50 and constrains the pitman to substantially up and down reciprocation by the cam 64. A pair of U shaped spring clips 138, 140 are fixed in side-by-side, insulated relation on a terminal block 142 which is fixed to the front face of the cross-bar 112. The upper ends of the electrodes 38, 40 may be releasably snapped into the spring clips and be supported thereby. Rotation of the cam 64 will provide up and down movement of the pitman 130, the cross-bar 112, and the electrodes 38, 40, from the upper position, shown in solid line, to the lower position, shown in phantom in FIG. 2.

The electrolytic cell assembly 32 comprises a hollow cylinder 142 having an upper portion 144 with a relatively larger internal diameter and a lower portion 146 with a relatively smaller internal diameter. The lower end of the cylinder is fixed onto a valve body 148 and is sealed thereto, by an O ring 150. The valve is substantially of the type which is disclosed in U.S. patent application Ser. No. 585,088, filed Oct. 7, 1966, by Nelson Kling. The valve is slidably mounted in a vertical, longitudinal bore 152 in a housing 154. A valve slide 156 is slidably mounted in a horizontal, diametrical bore 158 in the housing. The slide is semi-circular in cross-section with a flat upper surface 160, which mates with a fiat lower surface 162 of the body. The body 148 is resiliently biased against the slide 156 by a ring 164 which has a square flange. Four screws, not shown, one at each corner of the flange, draw the'ring towards the housing to compress a spring 166 against the body 148. The housing also has two horizontal bores 170 which are parallel to the bore 158 and have slots 172' through the common walls. The bores 170 are closed by a plate 174, and the housing is secured to the plate and the first wall 44 of the column by four machine screws 176. The wall 44, and the plate 174 are apertured to pass an outer sleeve 178, an inner bushing 180 and a cam follower rod 182. The front end of the rod 182 is received in a blind bore in the rear end of the valve slide 156 and is fixed thereto by a pin 184. The pin 184 projects through the slide, and each end of the pin passes through a respective slot 172 into a respective bore 170. A headed pin 186 and a compression spring 188 are disposed within each bore 170 respectively and serve to bias the pin 184 and the slide 156 rearwardly with the rod 182 against the cam 66. The cam 66 provides the slide 156 with three positions. In the middle position a bore 190 is in alignment with a bore 192 in the body 148 and a bore 194 in the housing 158, whereby fluid in the hollow cylinder 142 can dump through the valve into the blending receptacle 34. In a forward position, the slide 156 closes the bottom of the bore 192. In a rearward position, a bore 196, which is sealed to a conduit 198 which is connected to a waste receptacle, not shown, is disposed under the bore 192, whereby the contents of the hollow cylinder 142 can pass to waste.

The blending receptacle assembly 34 comprises a hollow cylinder 200 having an upper portion 202 with a relatively large internal diameter and a lower portion 204 with a relatively smaller internal diameter. The lower end of'the cylinder is on a body 206 and is sealed thereto by an O ring 208. The body 206 has a longitudinal blind bore 210 which communicates with a radial bore 212 and a radial, downwardly sloping bore 214. The body 206 is fixed to the front wall 44 by four machine screws 208. Disposed below the body 206 is a two position valve 216 'which is disclosed in S.N. 585,088 supra. This valve has a central port 218, the two alternative ports 220, 222, and a slide 223 which is biased by a spring 224 and is controlled by a solenoid 226. A conduit 228 interconnects the bore 212 with the port 220. A supply of wash liquid, not shown, is coupled to the port 222, by a conduit 230. The

port 218 is coupled by a conduit 232 to an automatic analysis apparatus, not shown, but which, solely for example, may be of the type shown in the U.S. Patent No. 3,211,050 granted to Milton H. Pelavin on Oct. 12, 1965, or in the U.S. Patent No. 3,200,651 granted to Edwin C. Whitehead on Aug. 17,1965. Under the control of the solenoid 226 and the bias spring 204, the slide of the valve is disposed to alternatively provide a flow of sample or of wash liquid through the port 218 to the analysis apparatus.

A diaphragm-type, solenoid operated valve 234, has an inlet 236 sealed into the bore 214, a diaphragm 238 controlled by a solenoid 240 and an outlet 242 coupled'to a waste receiving receptacle, not shown. The valve is fixed to and behind the front wall 44 by two brackets 244 and two nuts and bolts 246. When the solenoid is energized the valve drains the contents of the receptacle 210 to waste.

Two ports 246, 248 are sealed into the upper portion 144 of the electrolytic cell assembly 32. The conduit 246 is coupled by a conduit 250 to a solenoid-operated autopipette 250 which contains a supply of electrolyte. Energization of the solenoid of the autopipette causes the transmission of a predetermined volume of electrolyte through the conduit 246 into the electrolyte cell assembly 32. The port 240 is coupled by a conduit 254 to the outlet of a solenoid operated valve 256, whose inlet is coupled by a conduit 258 to a source of wash liquid, not shown. Energization of the solenoid of the valve provides a How of wash liquid into the electrolyte cell assembly.

A port 260 is coupled by a conduit 262 to the outlet of a solenoid operated valve 264, whose inlet is coupled by a conduit 266 to a source of wash liquid, not shown. Energization of the solenoid of the valve provides a flow of wash liquid into the blender receptacle.

The operation of the embodiment of FIG. 1 will be described as shown in FIG. 5.

Prior to the end of the preceding cycle, the switch 89 is closed by the cam 25 to energize the solenoid of the solenoid operated autopipette 252 to transmit a predetermined quantity of electrolyte into the receptacle 242 of the electrolytic cell 32.

Also prior to the end of the preceding cycle, the sample anode and a fresh electrode, if necessary, are manually snapped into the clips 138 and respectively.

To start the cycle, the switch 14 is pushed, which energizes the solenoid of the clutch 55 to engage the motor 54 with the output gear 58 to turn the programmer shaft 62. After about 1 second the actuator of the switch 84 rides out of a dwell of the cam 20 and maintains the solenoid energized.

From 0 through 5 seconds, the cam 64 through the pitman 130 lowers the electrodes into the electrolyte in the receptacle 142.

At 5 seconds, the actuator of the switch 82 rides out of a dwell in the cam 68 to provide current to the current timer 18.

Also at 5 seconds, the cam '61 actuates the switch 82 to energize the current timer 18, which has been preset for the desired interval for which current is to be applied to the electrodes, and this timer starts to run. Switches on the timer connects a current source, not shown, to the electrodes.

At 45 seconds, the actuator of the switch 84 falls into a dwell of the cam 20, deenerg-izing the programmer clutch 55 and halting the programmer shaft 62.

At any time between 65 through seconds, depending on the manual presetting, the current timer 18 runs out, switches current to the aspirate timer 20 and provides a pulse to the solenoid clutch to restart the programmer shifts the follower rod 182 to shift the valve slide 156 to align the bore 190 with the bores 192 and 194 to dump the sample-containing electrolyte from the container 142 into the container 200.

At 67 /2 seconds, the actautor of the switch 90 falls into the dwell of the cam 76- to energize the solenoid 226 of the valve 216 to shift its slide from the normal position wherein the wash liquid port 230 is coupled to the outlet port 232, to the position wherein the sample liquid port 220 is coupled to the port 232. Sample-containing electrolyte is now passed from the receptacle 200 through the valve 216 to the analysis apparatus.

At 70 seconds, the cam 66 shifts the rod 182 to shift the slide 156 to align the bore 196 with the bore 162. At the same time the actuator of the switch 86 falls into a dwell of the cam 72 for 5 seconds to energize the solenoid of the valve 256 to pass wash liquid from the supply through the conduit 254 into the receptacle 142 and out the conduit 198 until 75 seconds.

At 80 seconds, the cam 66 shifts the rod 182 to shift the slide 156 to obturate the bore 192.

At 90 seconds, the actautor of switch 92 falls into a dwell of cam 78 to switch current to the aspirate timer 20 for generating a programmer start pulse when timer 20 runs out.

At 95 seconds, the actuator of the switch 84 falls into a dwell on the cam 70 to deenergize the solenoid clutch to halt the programmer shaft 62.

At any time between 105 and 24-5 seconds, depending on the manual setting of the aspirate timer 20, this timer runs out and generates a pulse to restart the programmer. As-

suming the minimum period at 105 seconds, the solenoid clutch 75 is energized and the programmer shaft 62 starts.

At 107 /2 seconds, the actuator of the switch 90 rides out of the dwell of the cam 76 to deenergize the solenoid 226 of the valve 216, to shift the slide to the normal position, to halt the flow of sample containing liquid to the analyzer apparatus and to substitute a flow of wash liquid to the analysis apparatus.

Also at 107 /2 seconds the actuator of the switch 88 falls into a dwell of the cam 74, to energize the solenoid 240 of the valve 234 to drain the contents of the receptacle 200 to waste.

At 110 seconds, the actuator of the switch 94 falls into a dwell of the cam 80 for 5 seconds to energize the solenoid of the valve 264 to pass wash liquid from the supply through the conduit 262 into the receptacle 200 and out the valve 232.

At 117 /2 seconds, the actuator of the switch 82 falls into the dwell of the cam 68 to deenergize the current timer 18.

Also at 117 /2 seconds, the actautor of the switch 88 rides out of the dwell of the cam 74 to deenergize the solenoid 240 to close the valve 234.

At 120 seconds, the actuator of the switch 84 falls into the first dwell of the cam 70, deenergizing the clutch 65 and finally halting the programmer shaft 62.

It will be appreciated that the receptacle 142 may be made of the material, e.g. carbon, of which the cathode 40 is made. If the electrical supply is now connected to an anode 38 and such a receptacle, the cathode 40 may be omitted.

The apparatus shown in FIG. 6 is a modification of the apparatus of FIG. 1 to provide a fully automatic system which automatically processes a plurality of sample anodes.

A turntable assembly 300 which is adapted to reciprocate up and down and to rotate incrementally when up is substituted for the electrode support assembly 36 of FIG. 1. The receptacle 142' is made of electrode material, e.g. carbon, so that individual cathodes may be omitted. A control cam and switch are substituted for the cam 64 and pitman 130.

The turntable assembly 300 is of the type disclosed in U.S. Patent No. 2,872,894 issued Feb. 10, 1959 to Jack Isreeli, to which further reference for details should be made, noting particularly FIGS. 3 and 42 therein. Briefly, the assembly includes a turntable 302 which is supported by a shaft assembly 304. A plurality of clips 305 are fixed to the periphery of the turntable, and each is adapted to releasably hold a sample anode 38'.

Each of the anodes 38' and the cathode receptacle 142 are coupled to an electrical source though the current timer, as previously described.

Prior to the beginning of each cycle the turntable is elevated with an anode 38 disposed over the receptacle 142. At the start of the cycle the turntable is lowered to immerse the anode in the electrolyte in the receptacle 142. The dissolution, dump, and aspiration functions are accomplished as previously described. Subsequently the turntable is elevated to remove the anode from the receptacle 142 and rotated to station the next adjacent anode over the receptacle. These reciprocatory and rotational movements are provided by the shaft assembly 304 as shown in U.S. 2,872,894 supra. The assembly includes, inter alia, an outer tubular shaft 306 having a collar 308 and an inner tubular shaft 310 splined to the outer shaft. A motor 312 swings an arm 313 carrying a drive pin 314 to move a Geneva gear to-incrementally rotate the two shafts, and rotate a gear 316 which drives a gear 318 which is fixed on a shaft which swings a connecting arm 320 to raise and lower an arm 322 to raise and lower the collar 308 and the shaft 306. The motor 32 is energized and deenerg'ized by the control cam 64' which operates a double pole switch 324 which is coupled to a control circuit which includes the arm 313 and another double pole switch, as shown in U.S. 2,872,894, supra.

While there have been shown and described two prefixed embodiments of the invention, various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of the invention.

What is claimed is:

1. An anodic dissolution system comprising: a first container; an anode and a cathode, said anode defining a metallic sample; means for disposing electrolyte in said first container; means for disposing said cathode in electrical and liquid communication with the electrolyte; means for automatically disposing said anode in electrical and liquid communication with the electrolyte, and to subsequently remove it therefrom; means for automatically supplying a constant electri current to said electrodes for a predetermined interval while they are in communication with the electrolyte to electrolytically dissolve a portion of said metallic sample in said electrolyte; means for automatically receiving the sample-containing electrolyte from said first container and for transmitting a predetermined quantity thereof as a flowing stream to an analysis apparatus.

2. A system according to claim 1 wherein said first container serves as said cathode.

3. A system according to claim 1 wherein said means for receiving the sample-containing electrolyte and for transmitting a predetermined quantity thereof includes a second container disposed in liquid flow communication with said first container which blends the sample-containing electrolyte as it receives it; first valve means for withdrawing a predetermined quantity of the sample-containing electrolyte from said second container; and second valve means for withdrawing the remainder of the contents of said second container.

4. A system according to claim 3 further including means for automatically washing out said second container after the predetermined quantity of sample-containing electrolyte has been removed.

5. A system according to claim 3 further including means for automatically washing out said first container after said second container has received the samplecontaining electrolyte therefrom.

electrolyte.

References Cited UNITED STATES PATENTS Leisey 2325 3 Capuano 204195 Page 204l95 Hughes 204228 8 FOREIGN PATENTS 946,996 1/1964 Great Britain.

OTHER REFERENCES Preprint 90-37, The Electrochemical Society, 1946, pp. 469-473.

T. TUNG, Primary Examiner US. Cl. X.R. 

